The present invention relates to a communications system for mobile radio telephony comprising mobile devices and comprising modules which can be inserted into the mobile devices, with at least one subscriber territory being fixed inside the total territory covered by the communications system, within which subscriber territory communication takes place from and/or to the mobile devices under special conditions, and with means being provided by which it can be determined whether the mobile device is located inside the subscriber territory. The present invention further relates to a method of operating a communications system for mobile radio telephony using mobile devices and using modules which can be inserted into the mobile devices, with at least one subscriber territory being fixed inside the total territory covered by the communications system, within which subscriber territory communication takes place from and/or to the mobile devices under special conditions, and with a determination taking place whether the mobile device is located inside the subscriber territory.
A communications system and method of this type is known from EP 1 159 842. The known communications system covers a total territory which is divided into location areas and within which communication from and to the devices is possible. The total territory is divided into location areas which in turn have radio cells which are serviced by a transmitter and receiver station of the communications system. The mobile devices operable in the total territory have SIM modules which can be inserted into them and which permit an unambiguous identification of the mobile device provided therewith inside the communications system. Coordinates are furthermore stored on the SIM modules which consist of a location point with the coordinates Xh, Yh and a radius Rh which fixes a circle around the location point. At regular intervals, the transmitter and receiver stations of the communications system transmit identifiers of the associated radio cell and coordinates characteristic of the radio cell which can be received by mobile devices located in the region of the transmitter and receiver stations. A mobile device equipped with a corresponding application checks whether the received coordinates of the radio cell fall into the circle whose coordinates Xh, Yh, Rh are stored in a memory on the SIM module. If this is the case, i.e. if the coordinates of the radio cell lie within the circle, it is indicated to the user in the display of his device that his mobile device is located in the region of a transmitter and receiver station which is within the aforesaid circle. The background for the determination of subscriber territories of this type is the possibility of providing the user with special conditions, in particular reduced prices, provided his mobile device is located in a subscriber territory.
The examination whether the mobile device is located in a subscriber territory takes place on the part of the mobile device which is equipped with a corresponding software application. The software accesses the data Xh, Yh, Rh stored on the SIM module and checks with reference to the data received on the network side whether the mobile device is located in the subscriber territory. If this is the case, it will be indicated to the user on the display of the mobile device.
It is disadvantageous with the previously known communications system that the named examination of the association with a subscriber territory takes place by means of a software application located on the mobile device. Accordingly, especially equipped mobile devices are required. Mobile devices which do not have an application of this type can admittedly receive the identifiers and coordinates of the location areas and radio cells, but are not capable of determining whether an association of the location of the mobile device with a subscriber territory is present or not. It is therefore disadvantageous for the operator of a communications system of this type that he cannot offer the customer mobile devices which do no have the named application if the customer desires the aforesaid service. A further disadvantage results from the higher costs of mobile devices which have the required application.